1. Field of the Invention
The present invention relates to a trip cock device and, more particularly, to a trip cock fault detection device utilized on a rail vehicle.
2. Description of Related Art
Trip cock devices are mounted on rail cars and are connected to a brake pipe. The trip cock device is actuated by a trip arm positioned adjacent to the track. The trip arm may be positioned in an area that is restricted from train travel. When the train enters the prohibited area, the trip cock device is triggered by the trip arm and causes the brake pipe to vent to atmosphere thereby resulting in an emergency brake application.
A conventional trip cock device 1 is shown in FIGS. 1 and 2. The trip cock device 1 includes a handle 3, a cam dog 5, a piston assembly 7, and a pilot valve assembly 9. The trip cock device 1 initiates an emergency brake application when the handle 3 is rotated beyond a calibrated point. Moving the handle 3 causes the cam dog to move upwardly such that the cam dog engages the piston assembly 7. The movement of the piston assembly 7 causes an inlet port 11 to be blocked such that brake pipe air from a brake pipe inlet 13 is prevented from entering a chamber 15 on the topside of the piston assembly 7. The brake pipe air is then open to atmosphere via an exhaust opening 17 and the pressure of the brake pipe drops to initiate the emergency application of the brakes. The piston assembly 7 moves further upward to contact the pilot valve assembly 9 thereby causing the pilot valve to move upward and permitting the residual air in the chamber 15 to pass by the pilot valve and exhaust to atmosphere. When the brake pipe supply air drops below the force of a piston spring 19, the piston assembly 7 will return to its seat and the pilot valve spring returns the pilot valve to its seat. The handle 3 is returned to its position via a torsion spring (not shown).
With conventional trip cocks, such as the one shown in FIGS. 1-2, there are failure modes that cause the trip cock to malfunction. For example, with conventional trip cocks, the trip cock could become inoperable if the cam dog breaks or falls off or if the handle would fall off. If not properly manufactured or assembled, the cam dog, cam dog pin, cotter pin, handle, handle bolt, or handle bolt nut could lead to failures of the cam dog or handle. A broken or missing cam dog or missing handle would result in the main piston failing to open when the trip cock passes over a trip arm such that the emergency brakes are not applied when necessary.